Form for concrete.



J. R. SELFRIDGE.

FORM FOR CONCRETE.

APPLICATION FILED JULY 6. I914 1,163,375. Patented Dec. 7, 1915.

. INV EN TOR. WITNESSES: J/fi SEA F/F/D 6-5 7 BY Mum mM- fi ATTORNEYS.

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JAMES R. SELFRIDGE, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR TO SELFRIDGE HOLDING COMPANY, OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF CALIFORNIA.

FORM FOR CONCRETE.

Specification of Letters Patent.

Patented Dec. 7, 1915.

To all whom it may concern:

Be it known that I, JAMES R. Snnrnmen, a citizen of the United States, and a resident of the city and county of San Francisco, State of California, have invented certain new and useful Improvements in Forms for Concrete, of which the following is a specification.

The invention relates to forms which are to be used to support concrete before it has set.

The object of the invention is to provide a new concrete form.

A further object of the invention is to provide a light, cheap and eflicient form for concrete which may be quickly made and which may be used a plurality of times if desirable.

The invention possesses other advantageous features, some of which, with the foregoing, will be set forth at length in the following description, whereI shall outline in full that form of the invention which I have selected for illustration in the drawings accompanying and forming part of the present specification.

In the drawings I have shown one specific form of my generic invention, but it is to be understood that I do not limit myself to such form because my invention may be embodied in a multiplicity of forms, each being a species of my said invention. It is also to be understood that by the claims succeeding the description of my invention, I desire to cover the invention in whatever form it may be embodied.

Referring to said drawings: Figure 1 is a perspective View of a spiral wound tube from which the forms of my invention are made. Fig. 2 is a perspective view of one form of the concrete form. Fig. 3 is a perspective view of a modified form of the concrete form. Fig. 4 is a vertical section of a portion of concrete floor construction showin the application of one species of the form of my invention.

The form or mold of my invention is formed of a spiral wound tube formed of paper or similar material. The paper or material from which the tube is made may be of waterproof construction or the tube may be waterproofed after it is made. The tube consists of several spirally wound strips, one overlying the other and arranged in a staggered relation therewith, so that one sheet overlies and seals the joint formed in the adjacent sheet. The sheets are held together by glue or other adhesive, and the tube consists preferably of two spiral sheets one overlying the other, although a greater number of sheets may be used when desirable.

When the forms are to be used as supports for a concrete floor, the spirally wound tube 2 is split longitudinally, producing the segmental form 3 and the segmental form may be semi-circular, or the angle subtended by the segment may be greater or less than a straight angle, depending upon the circumstances of the concrete construction.

The edges of the segmental form may be waterproofed by dipping into a waterproofing material or otherwise applying the waterproofing material, or the edges may be bound with sheet metal strips 4 which are preferably crimped over the edges. The metal binding not only prevents the form from absorbing moisture at the edges, but also reinforces the form, and protects the edges from inury.

In Fig. 4, I have illustrated an application of the forms of my invention to concrete floor construction, but it is to be understood that the form is not limited in use to floor construction, but may be used in any type of concrete construction. In the application illustrated, the forms 3 are spaced from each other, forming a series of spaced arches and the forms are held in place by suitable supports which are removed after the concrete has set. The longitudinal edges of the forms rest on the timbers 5, and in the beam formed between the arches is placed the reinforcing material 6. The timbers 5 are supported by suitable framing 7 which may either be hung from the I-beams 8 or supported from beneath or both. The upper or crown portion of the form is held down by the reinforcing bar or bars 9, which preferably spans from one I-beam to the next and is attached to said beams. This arrangement of floor, formed of concrete beams separated by arches, is very economical in consumption of concrete in relation to the floor load, and I have found that by employing the arched forms having a diticular diameter.

On account of the fact that the forms are waterproofed, they do not absorb moisture and thereby become weakened, and may be removed after the concrete has set and be subsequently used. The forms are Very light, so that a great saving in labor is effected on account of their use, and they may be nested and stored in a small space.

I claim:

1. A form for concrete consisting of a segment of spirally wound paper tube provided on its edges with a metal binding.

2. In a form for concrete floor construe tion, a plurality of arched segments of spirally wound paper tube spaced apart laterally adapted to support the fresh concrete and supporting means engaging the longitudinal edges of the segments. 7

In testimony whereof, I have hereunto set my hand at San Francisco, California, this 29th day of June, 1914:.

JAMES R. SELFRIDGE.

In presence of- H. G. Pnos'r, J. BLGARDN R.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents J Washington, D. C. 

